Automatic cold starting devices for internal combustion engines

ABSTRACT

An automatic cold starting device for an internal combustion engine comprises, in an auxiliary passage leading into the main induction passage through which fuel/air mixture is normally supplied to the engine downstream of the main throttle valve, a second throttle valve and a fuel supply source controlled by a fuel valve, the second throttle valve and fuel valve being fully open when the engine is cold, being initially partly closed by suction in the auxiliary passage when the engine starts, and being then controlled for progressive further closing by a temperature sensitive device responsive to engine temperature.

United States Patent [191 Ross [ AUTOMATIC COLD STARTING DEVICES FORINTERNAL COMBUSTION ENGINES [75] Inventor: Gray Ernest Donald Ross,

Wiggington, England [73] Assignee: The Zenith Carburetter CompanyLimited, Middlesex, England [22] Filed: Apr. 12, 1972 [21] Appl. No.:243,312

[30] Foreign Application Priority Data Apr. 15, 1971 Great Britain9459/71 [52] US. Cl. 123/179 G, 123/180 R, 123/180 T [51] Int. Cl. F02m1/04, F02m 1/10 [58] Field of Search 123/179 G, 180 R, 180 T;

[ Sept. 17, 1974 Primary Examiner-Charles J. Myhre Assistant ExaminerW.Rutledge, Jr. Attorney, Agent, or Firm-Clelle W. Upchurch [5 7 ABSTRACTAn automatic cold starting device for an internal combustion enginecomprises, in an auxiliary passage leading into the main inductionpassage through which fuel/air mixture is normally supplied to theengine downstream of the main throttle valve, a second throttle valveand a fuel supply source controlled by a fuel valve, the second throttlevalve and fuel valve being fully open when the engine is cold, beinginitially partly closed by suction in the auxiliary passage when theengine starts, and being then controlled for progressive further closingby a temperature sensitive device responsive to engine temperature.

AUTOMATIC COLD STARTING DEVICES FOR INTERNAL COMBUSTION ENGINES Thisinvention relates to automatic cold starting devices for internalcombustion engines in which the constitution of a fuel/air mixturesupplied to the engine during starting from cold and warming up of theengine is changed firstly at the termination of the cranking period whenthe engine commences to run under its own power and is further changedprogressively with increase of engine temperature until normal runningtemperature is reached.

It is the object of the invention to provide an improved automatic coldstarting device.

According to one aspect of this invention there is provided an automaticcold starting device for an internal combustion engine having aninduction passage through which fuel/air mixture is normally supplied tothe engine and a main throttle valve in the said induction passage tocontrol the flow of fuel/air mixture therein during normal operation ofthe engine, said automatic cold starting device comprising, in anauxiliary passage opening at its outlet end into said induction passagedownstream of the main throttle valve and being connected to a source ofair at its inlet end, a second throttle valve, said second throttlevalve being so arranged that engine suction acting in said auxiliarypassage tends to urge it in the closing direction, a fuel supply sourcearranged to supply a metered quantity of fuel to said auxiliary passage,and a thermostatically controlled mechanism operative to limit theclosing of said second throttle valve so that, once the engine hasstarted to run, both the air flow in said auxiliary passage, and thesupply of fuel thereto, are progressively decreased with increase oftemperature.

Preferably the automatic cold starting device includes a fuel flowcontrol valve to control the supply of fuel from said source to saidauxiliary passage. The thermostatically controlled mechanism may beoperative to operate the fuel flow control valve.

According to another aspect of this invention there is provided anautomatic cold starting device for an internal combustion engine havingan induction passage through which fuel/air mixture is normally suppliedto the engine and a main throttle valve in the said induction passage tocontrol the flow of fuel/air mixture therein during normal operation ofthe engine, said automatic cold starting device comprising, in anauxiliary passage opening at its outlet end into said induction passagedownstream of the main throttle valve and being connected to a source ofair at its inlet end, a second throttle valve, said second throttlevalve being so arranged that engine suction acting in said auxiliarypassage tends to urge it in the closing direction, a fuel supply sourceconnected to said auxiliary passage, a fuel flow control valve tocontrol the supply of fuel from said source, and a thermostaticallycontrolled mechanism operative to limit the closing of said secondthrottle valve and to operate the fuel flow control valve so that oncethe engine has started to run, both the air flow in said auxiliarypassage, and the supply of fuel thereto, are progressively decreasedwith increase of temperature.

The inlet end of the auxiliary passage may be connected to the maininduction passage upstream of the main throttle valve.

Preferably, the second throttle valve is mounted on a spindle, and thethermostatically controlled mechanism comprises an arm fixed on saidspindle, one lever mounted pivotally on said spindle, and a biassingspring acting between the fixed arm and said one lever, relative angularmovement between the fixed arm and said one lever being limited, and theposition of said one lever being governed by a thermo-sensitive memberwhich is responsive to the temperature of an engine on which thestarting device is mounted, the thermosensitive device acting, withincrease of temperature, to rotate said one lever in a direction whichallows movement of the second throttle valve in the closing direction,the arrangement being such that, once the engine starts to run, thesecond throttle valve is moved relative to said one lever in the closingdirection by the action of engine suction, the amount of such closingmovement of the second throttle valve being limited to the permittedangular movement of said fixed arm relative to said one lever,progressive movement of the second throttle valve in the closingdirection being governed thereafter by the action of saidthermo-sensitive member on said one lever. Said one lever may carry acam follower, and a cam, which is engaged by the cam follower may beconnected operatively to the thermosensitive member which acts, withincrease of temperature, to rotate the cam in a direction such that theresulting movement of the follower rotates said one lever in thedirection to close said second throttle member. Said one lever may beheld in contact with the cam by a tension spring acting to urge said onelever in a direction to open the second throttle valve. The secondthrottle valve spindle may be coupled to the fuel flow control valve sothat movement of the second throttle valve in the closing direction isaccompanied by a corresponding decrease in the supply of fuel to theauxiliary passage. Said second throttle valve spindle may be coupled tothe fuel flow control valve by another lever which is mounted pivotallyon said spindle, relative angular movement between the other lever andthe fixed arm being limited and another biassing spring acting betweensaid other lever and the fixed arm and causing said other lever tofollow movement of the second throttle valve spindle until the fuel flowcontrol valve is closed.

The fuel flow control valve may comprise a profiled needle movableaxially in an orifice to vary the effective area thereof, the saidneedle carrying a sealing member operative to close the said orifice atthe end of the movement of said needle in the direction to reduce theeffective area of the orifice.

One embodiment of the invention will now be described by way of examplewith reference to the accompanying drawing, the single FIGURE of whichshows, in diagrammatic form, a carburetor having an auxiliary passagearound the main throttle valve and a second throttle valve in the saidauxiliary passage, together with a mechanism for controlling said secondthrottle valve and for controlling a fuel valve for admitting fuel tothe said auxiliary passage. In the drawing, the fuel valve is showndisconnected from the mecha nism but the connection is indicated by adotted line, the fuel supply connection between the fuel valve and theauxiliary throttle valve is shown by a chain dotted line, and the secondthrottle valve is shown twice for convenience, once to indicate itsposition in the auxiliary passage, and a second time to show itsconnection to the mechanism. The mechanism would, of course, becontained in a suitable housing, but it is not deemed necessary toillustrate this, since the design of the housing would be a simplematter for any competent engineer.

Referring to the drawing, the body of a carburetor of the fixed choketype is shown at 10, the main induction passage 11 therein being adaptedfor connection to the atmosphere through a conventional air cleaner (notshown) at its end 12, and for connection to the inlet manifold of aninternal combustion engine (not shown) at its end 13. A venturi throatis formed at 14 in the induction passage 11, and a main fuel supplypassage 15 is provided to supply fuel from a suitable source, such as afloat chamber, to the supply passage 15.

A main throttle valve 16 of the butterfly type is mounted in theinduction passage 11 down-stream of the throat 14, the throttle valvebeing provided with a conventional driver operated control mechanism(not shown) and having its closing limited by an adjustable stop 17.

An auxiliary passage 18 in the carburetor body opens at one end, at 19,into the main induction passage 11 upstream of the venturi throat l4 andat the other end, 21, into the said main induction passage downstream ofthe main throttle valve 16. A venturi throat 22 in the passage 18 hasopening thereinto a fuel supply passage 23, and a second throttle valve24 is mounted in the said auxiliary passage 18 downstream of the throat22, the throttle valve 24 being fixed on a spindle 25 which is offsetfrom the center of the said throttle valve 24 so as to have its axisalong a chord thereof, the arrangement being such that air flow towardsthe engine cylinders in the passage 18 tends to urge the said throttlevalve 24 towards a closed position. The spindle 25 is mounted insuitable bearings (not shown) and has fixed to a portion of it whichprojects through the wall of the passage 18, an arm 26 which carries twoposts 27 and 28 projecting on opposite sides thereof, parallel to thespindle 25 and extending respectively into notches 29, 31 one in each oftwo levers 32, 33 mounted to turn on the spindle 25, the notches 29 and31 both being wider than the posts 27 and 28, to allow relative angularmovement of both levers 32 and 33 with respect to the fixed arm 26.Torsion springs 34 and 35 acting respectively between the lever 32 andthe fixed arm and between the lever 33 and the fixed arm urge bothlevers in the same rotational direction relative to the auxiliarythrottle valve 24.

The fuel supply passage 23 opening into the auxiliary passage iscontrolled by a fuel flow control valve 36 comprising a tubular body 37in which is slidable a plunger 38 carrying a profiled needle 39 movableaxially in an orifice 41 defined by a restriction of the bore of thetubular body 37, the plunger 38 also carrying, at the larger-diameterend of the profiled needle 39, a sealing ring 42 adapted to close theorifice 41.

A projection 43 on the lever 32 engages a lateral notch 44 in the valveplunger 38 so that angular movement of the lever 32 moves the plunger 38axially in the bore, movement of the lever in an angular directioncorresponding to closing movement of the second throttle valve 24, whichdirection is indicated by the arrow A in the drawing, moving the plungerin a direction to progressively increase the restriction of the orifice41 and ultimately to close that orifice. The lower end of the bore ofthe valve body 37 is open to a fuel supply reservoir indicateddiagrammatically at 45, and a lateral port 46 in the said bore, abovethe orifice 41, is connected, as indicated by the chain-dotted line 47,to the fuel supply passage 23.

The torsion spring 34 acts in a direction such that the clearanceprovided by the difference in width between the post 27 and the notch 29is on the side of the post which is ahead of the said post in thedirection of closing of the second throttle valve and, after the fuelsupply control valve is fully closed, the spindle 25 can continue torotate in the closing direction of the second throttle valve, furtherloading the spring 34.

The other lever 33 carries a cam follower pin 48 engaging the profilededge of a cam 49 the angular position of which is controlled by abi-metallic coil 51 which is sensitive to change of temperature of theengine and with increase of temperature, rotates the cam 49 in adirection to turn the said lever 33 in the same direction as that,indicated by the arrow A, in which the spindle 25 rotates with closingmovement of the second throttle valve 24. The cam 49 is, of course,rotatably mounted on a spindle, (not shown) the bi-metallic coil 51being anchored at its inner end and engaging a post 52 on the cam 49 atits outer end.

The torsion spring 34 acting between the first lever 32 and the arm 26urges that lever in such a direction that it tends to follow the closingmovement of the second throttle valve 24 and cause simultaneous closingmovement of the fuel supply orifice, and the torsion spring 35 actingbetween the other lever 33 and the said arm tends to urge the secondthrottle valve 24 towards its open position to the maximum degree ofopening permitted by the cam.

The lever 33 is acted on by a tension spring 53 provided with a fixedanchorage at 54 and tending to urge the follower 48 aginst the profileof the cam 49. Thus the position of the lever 33 is at all timesdetermined by the position of the cam 49. The torsion spring 35 urgesthe arm 26 and spindle 25 in the opposite angular direction to the arrowA, so that the said arm and spindle tend to move as far in thatdirection as is allowed by the clearance of the post 28 in the notch 31,thus positioning the second throttle valve 24 in the most widely openposition allowed by the cam 49. This is assuming that there is no airflow in the auxiliary passage 18.

When an engine to which the cold starting device is fitted is cold, thebi-metallic coil holds the cam 49 in a position such that the secondthrottle valve 24 takes up its fully open position. The lever 32 beingheld by the associated post 27 on the arm 26, locates the plunger 38 inits corresponding position.

When the engine is cranked for starting the parts remain in thesepositions until the engine commences to run under its own power, whenthe air flow velocity increase in the auxiliary passage 18 acts to urgethe second throttle valve 24 towards its closed position, the closingmovement being limited by the angular extent of the notch 31 in thelever 33. The lever 32 follows the movement of the second throttle valve24 and reduces the effective area of the fuel orifice 41. As the enginewarms up, the cam 49 is rotated by the bi-metallic coil 51 to allowprogressive further closing of the second throttle valve 24 and of thefuel orifice 41, until the sealing ring 42 on the profiled needle 39closes the said fuel orifice and shuts off the auxiliary fuel supply.The second throttle valve 24, at this stage, is not fully closed, sothat a greater flow of air is available than can take place through themain throttle valve 16, providing a fast idle condition. The cam 49continues to be moved until a predetermined temperature is reached, thepost 27 on the arm 26 which co-operates with the first lever 32 movingaway from the side of the notch 29 in that lever with which it has beenin engagement, until the throttle valve 24 is closed or brought to aposition of minimum opening at which it remains for normal running.

It will be apparent that the rate of closing of the second throttlevalve 24 in relation to temperature rise can be determined by theprofile of the cam 49, and the rate of change of fuel supply can bedetermined by selection of the profile of the needle 39, so that the airand fuel supply can be independently determined. The initial reductionin auxiliary mixture supply due to air flow in the passage 18 when theengine commences to run can be determined by selecting the length of thenotch 31 in the lever 33.

While the automatic cold starting device according to the invention hasbeen shown and described as applied to a carburetor of the fixed choketype, it may also be used with carburetors of the constant depressiontype, a passage corresponding to the passage 18 shown in the drawingbeing provided, which passage leads from a position at which it receivesair at substantially atmospheric pressure into the induction passagedownstream of the main throttle valve. Alternatively the automatic coldstarting device according to the invention may be used with carburetorsof either the constant depression type or the fixed choke type, apassage corresponding to the passage 18 shown in the drawing beingprovided which leads from the induction passage between the throat andthe main throttle valve into the induction passage downstream of themain throttle valve.

As an alternative to the bi-metallic coil 51 described above, otherforms of thermo-sensitive member, such as a thermo-sensitive capsule,may be employed.

I claim:

1. In an internal combustion engine having an induction passage throughwhich fuel/air mixture is normally supplied to the engine and a mainthrottle valve in the said induction passage to control the flow offuel/air mixture therein during normal operation of the engine, anautomatic cold starting device comprising, means defining an auxiliarypassage opening at its outlet end into said induction passage downstreamof the main throttle valve and being connected to a source of air at itsinlet end, a second throttle valve, in said auxiliary passage, saidsecond throttle valve being so arranged that engine suction acting insaid auxiliary passage tends to urge it in the closing direction, a fuelsupply source, a fuel flow control valve to control the supply of fuelfrom said source to said auxiliary passage, and a thermostaticallycontrolled mechanism operative to operate the fuel flow control valveand to limit the closing of said second throttle valve so that, once theengine has started to run, both the air flow in said auxiliary passage,and the supply of fuel thereto, are progressively decreased withincrease of temperature.

2. In an internal combustion engine having an induction passage throughwhich fuel/air mixture is normally supplied to the engine and a mainthrottle valve in the said induction passage to control the flow offuel/air mixture therein during normal operation of the engine, anautomatic cold starting device comprising, means defining an auxiliarypassage opening at its outlet end into said induction passage downstreamof the main throttle valve and being connected to a source of air at itsinlet end, a second throttle valve in said auxiliary passage, saidsecond throttle valve being so arranged that engine suction acting insaid auxiliary passage tends to urge it in the closing direction, a fuelsupply source connected to said auxiliary passage, a fuel flow controlvalve to control the supply of fuel from said source, and athermostatically controlled mechanism operative to limit the closing ofsaid second throttle valve and to operate the fuel flow control valve,so that, once the engine has started to run, both the air flow in saidauxiliary passage, and the supply of fuel thereto, are progressivelydecreased with increase of temperature.

3. An automatic cold starting device according to claim 2, wherein theinlet end of the auxiliary passage is connected to the main inductionpassage upstream of the main throttle valve.

4. In an internal combustion engine having an induction passage throughwhich fuel/air mixture is normally supplied to the engine and a mainthrottle valve in the said induction passage to control the flow offuel/air mixture therein during normal operation of the engine, anautomatic cold starting device comprising, means defining an auxiliarypassage opening at its outlet end into said induction passage downstreamof the main throttle valve and being connected to a source of air at itsinlet end, a second throttle valve in said auxiliary passage, saidsecond throttle valve being mounted on a spindle, said second throttlevalve being so arranged that engine suction acting in said auxiliarypassage tends to urge it in the closing direction, a fuel supply sourceconnected to said auxiliary passage, a fuel flow control valve tocontrol the supply of fuel from said source, and a thermostaticallycontrolled mechanism operative to limit the closing of said secondthrottle valve and to operate the fuel flow control valve, saidthermostatically controlled mechanism comprises an arm fixed on saidspindle, one lever mounted pivotally on said spindle, and a biassingspring acting between the fixed arm and said one lever, relative angularmovement between the fixed arm and said one lever being limited, and theposition of said one lever being governed by a thermo-sensitive memberwhich is responsive to the temperature of an engine on which thestarting device is mounted, the thermo-sensitive device acting withincrease of temperature, to rotate said one lever in a direction whichallows movement of the second throttle valve in the closing direction,the arrangement being such that, once the engine starts to run, thesecond throttle valve is moved relative to said one lever in the closingdirection by the action of engine suction, the amount of such closingmovement of the second throttle valve being limited to the permittedangular movement of said fixed arm relative to said one lever,progressive movement of the second throttle valve in the closingdirection being governed thereafter by the action of saidthermo-sensitive member on said one lever, said one lever carrying a camfollower, and a cam, which is engaged by the cam follower, beingconnected operatively to the thermo-sensitive member which acts, withincrease of temperature to rotate the cam in a direction such that theresulting movement of the follower rotates said one lever in thedirection to close said second throttle member.

5. An automatic cold starting device according to claim 4, wherein saidone lever is held in contact with the cam by a tension spring acting tourge said one lever in a direction to open the second throttle valve.

6. An automatic cold starting device according to claim 4, wherein thespindle is coupled to the fuel flow control valve so that movement ofthe second throttle valve in the closing direction is accompanied by acor responding decrease in the supply of fuel to the auxiliary passage.

7. An automatic cold starting device according to claim 6, wherein saidspindle is coupled to the fuel flow control valve by another lever whichis mounted pivotally on said spindle, relative angular movement betweenthe other lever and the fixed arm being limited and another biassingspring acting between said other lever and the fixed arm and causingsaid other lever to follow movement of the spindle until the fuel flowcontrol valve is closed.

8. An automatic cold starting device according to claim 2, wherein thefuel flow control valve comprises a profiled needle movable axially inan orifice to vary the effective area thereof, the said needle carryinga sealing member operative to close the said orifice at the end of themovement of said needle in the direction to reduce the effective area ofthe orifice.

9. In an internal combustion engine having an induction passage throughwhich fuel/air mixture is normally supplied to the engine and a mainthrottle valve in the said induction passage to control the flow offuel/air mixture therein during normal operation of the engine, anautomatic cold starting device comprising, means defining an auxiliarypassage opening at its outlet end into said induction passage downstreamof the main throttle valve and being connected to a source of air at itsinlet end, a second throttle valve, in said auxiliary passage saidsecond throttle valve being so arranged that engine suction acting insaid auxiliary passage tends to urge it in the closing direction, a fuelsupply source arranged to supply metered quantities of fuel to saidauxiliary passage, a thermostatically controlled mechanism operative tolimit the closing of said second throttle valve, said thermostaticallycontrolled mechanism comprises an arm fixed on a spindle, one levermounted pivotally on said spindle, and a biassing spring acting betweenthe fixed arm and said one lever, relative angular movement between thefixed arm and said one lever being limited, and the position of said onelever being governed by a thermo-sensitive member which is responsive tothe temperature of an engine on which the starting device is mounted,the thermosensitive device acting with increase of temperature, torotate said one lever in a direction which allows movement of the secondthrottle valve in the closing direction, the arrangement being suchthat, once the engine starts to run, the second throttle valve is movedrelative to said one lever in the closing direction by the action ofengine suction, the amount of such closing movement of the secondthrottle valve being limited to the permitted angular movement of saidfixed arm relative to said one lever, progressive movement of the secondthrottle valve in the closing direction being governed thereafter by theaction of said thermo-sensitive member on said one lever.

1. In an internal combustion engine having an induction passage throughwhich fuel/air mixture is normally supplied to the engine and a mainthrottle valve in the said induction passage to control the flow offuel/air mixture therein during normal operation of the engine, anautomatic cold starting device comprising, means defining an auxiliarypassage opening at its outlet end into said induction passage downstreamof the main throttle valve and being connected to a source of air at itsinlet end, a second throttle valve, in said auxiliary passage, saidsecond throttle valve being so arranged that engine suction acting insaid auxiliary passage tends to urge it in the closing direction, a fuelsupply source, a fuel flow control valve to control the supply of fuelfrom said source to said auxiliary passage, and a thermostaticallycontrolled mechanism operative to operate the fuel flow control valveand to limit the closing of said second throttle valve so that, once theengine has started to run, both the air flow in said auxiliary passage,and the supply of fuel thereto, are progressively decreased withincrease of temperature.
 2. In an internal combustion engine having aninduction passage through which fuel/air mixture is normally supplied tothe engine and a main throttle valve in the said induction passage tocontrol the flow of fuel/air mixture therein during normal operation ofthe engine, an automatic cold starting device comprising, means definingan auxiliary passage opening at its outlet end into said inductionpassage downstream of the main throttle valve and being connected to asource of air at its inlet end, a second throttle valve in saidauxiliary passage, said second throttle valve being so arranged thatengine suction acting in said auxiliary passage tends to urge it in theclosing direction, a fuel supply source connected to said auxiliarypassage, a fuel flow control valve to control the supply of fuel fromsaid source, and a thermostatically controlled mechanism operative tolimit the closing of said second throttle valve and to operate the fuelflow control valve, so that, once the engine has started to run, boththe air flow in said auxiliary passage, and the supply of fuel thereto,are progressively decreased with increase of temperature.
 3. Anautomatic cold starting device according to claim 2, wherein the inletend of the auxiliary passage is connected to the main induction passageupstream of the main throttle valve.
 4. In an internal combustion enginehaving an induction passage through which fuel/air mixture is normallysupplied to the engine and a main throttle valve in the said inductionpassage to control the flow of fuel/air mixture therein during Normaloperation of the engine, an automatic cold starting device comprising,means defining an auxiliary passage opening at its outlet end into saidinduction passage downstream of the main throttle valve and beingconnected to a source of air at its inlet end, a second throttle valvein said auxiliary passage, said second throttle valve being mounted on aspindle, said second throttle valve being so arranged that enginesuction acting in said auxiliary passage tends to urge it in the closingdirection, a fuel supply source connected to said auxiliary passage, afuel flow control valve to control the supply of fuel from said source,and a thermostatically controlled mechanism operative to limit theclosing of said second throttle valve and to operate the fuel flowcontrol valve, said thermostatically controlled mechanism comprises anarm fixed on said spindle, one lever mounted pivotally on said spindle,and a biassing spring acting between the fixed arm and said one lever,relative angular movement between the fixed arm and said one lever beinglimited, and the position of said one lever being governed by athermo-sensitive member which is responsive to the temperature of anengine on which the starting device is mounted, the thermo-sensitivedevice acting with increase of temperature, to rotate said one lever ina direction which allows movement of the second throttle valve in theclosing direction, the arrangement being such that, once the enginestarts to run, the second throttle valve is moved relative to said onelever in the closing direction by the action of engine suction, theamount of such closing movement of the second throttle valve beinglimited to the permitted angular movement of said fixed arm relative tosaid one lever, progressive movement of the second throttle valve in theclosing direction being governed thereafter by the action of saidthermo-sensitive member on said one lever, said one lever carrying a camfollower, and a cam, which is engaged by the cam follower, beingconnected operatively to the thermo-sensitive member which acts, withincrease of temperature to rotate the cam in a direction such that theresulting movement of the follower rotates said one lever in thedirection to close said second throttle member.
 5. An automatic coldstarting device according to claim 4, wherein said one lever is held incontact with the cam by a tension spring acting to urge said one leverin a direction to open the second throttle valve.
 6. An automatic coldstarting device according to claim 4, wherein the spindle is coupled tothe fuel flow control valve so that movement of the second throttlevalve in the closing direction is accompanied by a correspondingdecrease in the supply of fuel to the auxiliary passage.
 7. An automaticcold starting device according to claim 6, wherein said spindle iscoupled to the fuel flow control valve by another lever which is mountedpivotally on said spindle, relative angular movement between the otherlever and the fixed arm being limited and another biassing spring actingbetween said other lever and the fixed arm and causing said other leverto follow movement of the spindle until the fuel flow control valve isclosed.
 8. An automatic cold starting device according to claim 2,wherein the fuel flow control valve comprises a profiled needle movableaxially in an orifice to vary the effective area thereof, the saidneedle carrying a sealing member operative to close the said orifice atthe end of the movement of said needle in the direction to reduce theeffective area of the orifice.
 9. In an internal combustion enginehaving an induction passage through which fuel/air mixture is normallysupplied to the engine and a main throttle valve in the said inductionpassage to control the flow of fuel/air mixture therein during normaloperation of the engine, an automatic cold starting device comprising,means defining an auxiliary passage opening at its outlet end into saidinduction passage downstream of the main throttLe valve and beingconnected to a source of air at its inlet end, a second throttle valve,in said auxiliary passage said second throttle valve being so arrangedthat engine suction acting in said auxiliary passage tends to urge it inthe closing direction, a fuel supply source arranged to supply meteredquantities of fuel to said auxiliary passage, a thermostaticallycontrolled mechanism operative to limit the closing of said secondthrottle valve, said thermostatically controlled mechanism comprises anarm fixed on a spindle, one lever mounted pivotally on said spindle, anda biassing spring acting between the fixed arm and said one lever,relative angular movement between the fixed arm and said one lever beinglimited, and the position of said one lever being governed by athermo-sensitive member which is responsive to the temperature of anengine on which the starting device is mounted, the thermo-sensitivedevice acting with increase of temperature, to rotate said one lever ina direction which allows movement of the second throttle valve in theclosing direction, the arrangement being such that, once the enginestarts to run, the second throttle valve is moved relative to said onelever in the closing direction by the action of engine suction, theamount of such closing movement of the second throttle valve beinglimited to the permitted angular movement of said fixed arm relative tosaid one lever, progressive movement of the second throttle valve in theclosing direction being governed thereafter by the action of saidthermo-sensitive member on said one lever.